Electronic devices installed in a vehicle have been increased significantly in their number and variety along with recent digitalization of vehicle parts. Generally, electronic devices may be used throughout the vehicle, such as in a power train control system (e.g., an engine control system, an automatic transmission control system, or the like), a body control system (e.g., a body electronic equipment control system, a convenience apparatus control system, a lamp control system, or the like), a chassis control system (e.g., a steering apparatus control system, a brake control system, a suspension control system, or the like), a vehicle network (e.g., a controller area network (CAN), a FlexRay-based network, a media oriented system transport (MOST)-based network, or the like), a multimedia system (e.g., a navigation apparatus system, a telematics system, an infotainment system, or the like), and so forth.
The electronic devices used in each of these systems are connected via the vehicle network, which supports functions of the electronic devices. For instance, the CAN may support a transmission rate of up to 1 Mbps and support automatic retransmission of colliding messages, error detection based on a cycle redundancy interface (CRC), or the like. The FlexRay-based network may support a transmission rate of up to 10 Mbps and support simultaneous transmission of data through two channels, synchronous data transmission, or the like. The MOST-based network is a communication network for high-quality multimedia, which may support a transmission rate of up to 150 Mbps.
Meanwhile, the telematics system and the infotainment system, like most enhanced safety systems of a vehicle do, require higher transmission rates and system expandability. However, the CAN, FlexRay-based network, and the like may not sufficiently meet such requirements. The MOST-based network, in particular, may support a higher transmission rate than the CAN or the FlexRay-based network. However, applying the MOST-based network to vehicle networks can be costly. Due to this, an Ethernet-based network is often utilized as a vehicle network. The Ethernet-based vehicle network may support bi-directional communication through one pair of windings and may support a transmission rate of up to 10 Gbps.
Specifically, the Ethernet-based vehicle network may include a plurality of communication nodes (e.g., electronic devices and switches, etc.) that perform Ethernet-based communications. The plurality of communication nodes included in the vehicle network are required to acquire time synchronization to perform communications with each other. For this, the plurality of communication nodes periodically measure link delays between the plurality of communication nodes. Here, the plurality of communication nodes may transmit messages for measuring the link delays periodically according to a predetermined cycle even though a measured difference between the link delays is not so large. Accordingly, there is a problem that the plurality of communication nodes consume energy unnecessarily due to transmission of periodic messages and excessively frequent measurements of link delays.